Transmission Control Protocol Vegas Research Articles

A survey of transmission control protocol variants

TCP (Transmission Control Protocol), is a reliable connection oriented end-to-end protocol. It contains within itself, mechanisms for ensuring reliability by requiring the receiver to acknowledge the segments that it receives. The network is not perfect and a small percentage of packets are lost enroute, either due to network error or due to the fact that there is congestion in the network and the routers are dropping packets. TCP ensures reliability by starting a timer whenever it sends a segment. If it does not receive an acknowledgement from the receiver within the ‘time-out’ interval then it retransmits the segment. In this paper a review of various TCP is carried out. There are a number of TCP variants for application in the management of network efficiency in terms of network congestion and transmission efficiency. These variants include: - TCP Tahoe, TCP Reno, TCP New Reno, TCP Vegas, TCP SACK, TCP FACK, TCP Asym, TCP RBP, Full TCP and TCP CUBIC. Therefore, the main objective of this paper is to study the tcp types on the network performance variances. All have different features and advantages but with maximal throughput as main objective, which are termed as the clones of TCP, have been incorporated into TCP/IP protocol for handling congestion efficiently in different network scenarios.

Impact of buffering time reduction on false congestion detection in TCP vegas over OBS networks

Since Transmission Control Protocol (TCP) is the dominant protocol on the Internet and optical burst switching (OBS) networks represent the optical transmission solution that can meet future high bandwidth requirements, TCP and OBS networks represent a possible combination for the next-generation Internet. However, a problem with this combination model is that operations at the OBS layer need to be controlled so that false congestion detection at the TCP layer is minimised. Considering the combination of TCP Vegas and OBS, congestion detection at the TCP layer is based on the round-trip time (RTT), where congestion is detected if the current RTT exceeds a given RTTmax. The extra delay may be due to some actual loss, but it may also be due to the extended execution time caused by some OBS layer operations. Therefore, reducing the time of operations at the OBS layer will reduce false congestion detection at the TCP layer. This paper investigates the impact of reducing the buffering time at the ingress node on the false congestion detection rate at the TCP layer. The reduction of the burst buffering time is accomplished by nesting the offset time in the assembly time. The simulation results and analysis show that the transmission efficiency in TCP Vegas over OBS networks is significantly improved; the throughput remains high, and the delivery success rate is significantly increased compared to the conventional buffering mode.

Analysis of TCP Issues and Their Possible Solutions in the Internet of Things

The Internet of Things (IoT) is widely known as a revolutionary paradigm that offers communication among different types of devices. The primary goal of this paradigm is to implement efficient and high-quality smart services. It requires a protocol stack that offers different service requirements for inter-communication between different devices. Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are used as transport layer protocols in IoT to provide the quality of service needed in various IoT devices. IoT encounters many shortcomings of wireless networks, while also posing new challenges due to its uniqueness. When TCP is used in an IoT system, a variety of challenging issues have to be dealt with. This paper provides a comprehensive survey of various issues which arises due to the heterogeneous characteristics of IoT. We identify main issues such as Retransmission Timeout (RTO) algorithm issue, congestion and packet loss issue, header overhead, high latency issue, link layer interaction issue, etc. Moreover, we provide several most probable solutions to the above-mentioned issues in the case of IoT scenarios. RTO algorithm issue has been resolved by using algorithms such as CoCoA, CoCoA+, and CoCoA++. Apart from these, the high latency issue has been solved with the help of a long lived connection and TCP Fast open. Congestion and packet loss issue has been resolved by using several TCP variants such as TCP New Reno, Tahoe, Reno, Vegas, and Westwood.

Comparative Analysis of TCP, TCP-Vegas, and SCTP in Mobile Ad-Hoc Networks

Mobile Ad hoc Networks (MANET) is a collection of mobiles and smart devices that communicates using wireless links. These types of networks are growing at the lightning speed and are being used at a large scale than ever before because of their high availability and mobility. As the usage of MANET devices increase, the challenges also increase for example the proper delivery of data or information to every mobile node. Traditionally, transmission control protocol (TCP) is used for delivery but it does not fit in all scenarios due to some of its limitations such as network congestion and quick recovery in case of link failure. In this, a comparative analysis of TCP is performed with the stream control transmission protocol (SCTP) and a TCP variant called TCP VEGAS. Several ad hoc scenarios are proposed with varying numbers of mobile nodes, i.e. 11, 21 and 31. The results obtained indicate that SCTP outperforms TCP and VEGAS in throughput. While using SCTP the packet lifetime is also small i.e. 0.19 seconds. The link utilization of SCTP is better than TCP and VEGAS. However, TCP increases its link utilization more than VEGAS for the nodes in MANET of large delay.

Improvement of TCP Vegas algorithm based on forward direction delay

Satellite networks transmit data through the space communications protocol specification transport protocol and uses transmission control protocol (TCP) Vegas as the congestion control algorithm. However, TCP Vegas does not have a suitable solution for the asymmetric bandwidth of satellite networks. Therefore, the reverse link of asymmetric bandwidth frequently causes congestion in satellite networks. This issue is addressed by reducing the congestion window with the occurrence of reverse link congestion, thereby simultaneously reducing the forward link throughput of the satellite network. In this study, a forward congestion control algorithm for the TCP Vegas algorithm based on time delay, which is called Vegas_FDD (forward direction delay), is proposed to mitigate congestion by dividing it into different types (forward and backward) and to improve network bandwidth utilisation. The suitability and effectiveness of the proposed algorithm are verified through simulation on Opnet software.

Performance Evaluation of Reactive Routing Protocols in MANETs in Association with TCP Newreno

We inspect the performance of TCP NewReno protocol for data transfer in Mobile Ad hoc networks (MANETs). Dynamic Source Routing (DSR) protocols and AdHoc On-demand Distance Vector (AODV) are standard reactive routing protocols widely used in MANETs. In addition we also have to consider Transmission Control Protocol (TCP) as essential for MANETs since it is one of the widely used internet protocol for dependable data transmission. TCP has its variants namely TCP Reno, TCP NewReno , TCP Vegas and TCP SACK. In this paper we are evaluating the performance of DSR and AODV in association with TCP Newreno with respect to various parameters such as Average throughput, instant throughput, residual energy, packet delivery ratio. The ns-2 network simulator was used for simulation.

Performance Evaluation of TCP Vegas over TCP Reno and TCP NewReno over TCP Reno

In the Transport layer, there are two types of Internet Protocol are worked, namely- Transmission Control Protocol (TCP) and User datagram protocol (UDP). TCP provides connection oriented service and it can handle congestion control, flow control, and error detection whereas UDP does not provide any of service. TCP has several congestion control mechanisms such as TCP Reno, TCP Vegas, TCP New Reno, TCP Tahoe, etc. In this paper, we have focused on the behavior performance between TCP Reno and TCP Vegas, TCP New Reno over TCP Reno, when they share the same bottleneck link at the router. For instigating this situation, we used drop-tail and RED algorithm at the router and used NS-2 simulator for simulation. From the simulation results, we have observed that the performance of TCP Reno and TCP Vegas is different in two cases. In drop tail algorithm, TCP Reno achieves better Performance and throughput and act more an aggressive than Vegas. In Random Early Detection (RED) algorithm, both of congestion control mechanism provides better fair service when they coexist at the same link. TCP NewReno provides better performance than TCP Reno.

Improving Performance of Optical Networks by a Probable Approach

Abstract Optical Burst Switching (OBS) networks are new emerging techniques that alternate Optical Circuit Switching (OCS) and Optical Packet Switching (OPS) techniques. The high bandwidth of fiber links in these networks, besides WDM (Wavelength Division Multiplexing) helps the Internet to handle the heavy traffic. OBS networks have an important issue that needs to be tackled. These networks are bufferless in their nature, so when two bursts are trying to reserve one wavelength one of them is dropped. This drop can be assumed as an indicator of congestion; as a result, the sending rate will be decreased, despite the fact that the network may not be congested. So, wired protocols like TCP (Transmission Control Protocol) cannot work to their high potential in OBS networks. In this paper, we propose a new scheme based on a probable approach that can distinguish burst drops caused by contentions from burst drops caused by contention, so we can improve the performance of the network. Extensive simulative studies show that the proposed algorithm outperforms TCP Vegas in terms of throughput and packet delivery count.

RESEARCH ON TCP/IP CONGESTION CONTROL BASED ON NS-2 NETWORK SIMULATION PLATFORM

The emergence of the Internet facilitates people's lives. Although the network bandwidth increases rapidly, channel resources are limited and network congestion is bound to occur. In order to alleviate network congestion and improve service quality, this paper simply introduced four transmission control protocol (TCP) congestion control algorithms and network simulation-2 (NS-2) network simulation platform for simulating the network environment. Then the performance of four TCP congestion control algorithms in congested network and high bandwidth networks is simulated and analyzed on NS-2 simulation platform. The results showed that TCP Vegas has stable performance in both congested and high-bandwidth networks, and not only the change of cwnd is stable, but also the total number of packets sent and the average throughput are more, and the packet loss rate is 0; the performance of the other three algorithms is consistent in high bandwidth network, In crowded networks, TCP Tahoe performs worst, TCP Reno performs generally, and TCP SACK performs well; TCP Vegas performs poorly on average latency. In summary, TCP Vegas can be used stably in congested networks and high bandwidth networks, but considering the average delay, it is more inclined to apply the other three algorithms in high bandwidth networks.

Comparative Performance Evaluation of TCP with Identical and Cross-Variant Congestion Control

The Transmission Control Protocol (TCP), a key functional building block of the Internet, operates as a rate-adaptive end-to-end protocol at the Transport Layer of the network protocol stack. It regulates the prevailing load conditions within the network by getting the source node to adapt the packet transfer rate in accord with the processing capacity of the receiver. The regulation is enforced by means of dropping of packets on the part of the receiver. The TCP sender then reduces the packet injection rate so as to allow the network to recover from congestion. The focus of this paper is performance evaluation of certain notable TCP congestion avoidance algorithms, namely, Vegas, Reno and New Reno. Specifically, a number of performance measures have been analysed based on ns-2 simulation data where the scenarios involved TCP flows operating with identical and cross-variant congestion control mechanisms. Congestion window behaviour, packet loss, throughput, transmission delay and jitter are the performance criteria studied with the setup mentioned. In the flows with identical variants, Vegas outperforms other TCP variants. However, TCP Vegas has been observed to contribute to unfair appropriation of the resources in the cross-variant setting.

A review on transport layer protocol performance for delivering video on an adhoc network

The transport layer protocol is responsible for the end to end data transmission. Transmission control protocol (TCP) provides a reliable connection and user datagram protocol (UDP) offers fast but unguaranteed data transfer. Meanwhile, the 802.11 (wireless fidelity/WiFi) networks have been widely used as internet hotspots. This paper evaluates TCP, TCP variants and UDP performances for video transmission on an adhoc network. The transport protocol - medium access cross-layer is proposed by prioritizing TCP acknowledgement to reduce delay. The NS-2 evaluations show that the average delays increase linearly for all the evaluated protocols and the average packet losses grow logarithmically. UDP produces the lowest transmission delay; 5.4% and 5.8% lower than TCP and TCP variant, but experiences the highest packet loss. Both TCP and TCP Vegas maintain packet loss as low as possible. The proposed cross-layer successfully decreases TCP and TCP Vegas delay about 0.12 % and 0.15%, although losses remain similar.

A Survey on TCP Congestion Control Schemes in Guided Media and Unguided Media Communication

Transmission Control Protocol (TCP) is a widely used end-to-end transport protocol in the Internet. This End to End delivery in wired (Guided) as well as wireless (Unguided) network improves the performance of transport layer or Transmission control Protocol (TCP) characterized by negligible random packet losses. This paper represents tentative study of TCP congestion control principles and mechanisms. Modern implementations of TCP hold four intertwined algorithms: slow start, congestion avoidance, fast retransmits, and fast recovery in addition to the standard algorithms used in common implementations of TCP. This paper describes the performance characteristics of four representative TCP schemes, namely TCP Tahoe, Reno, New Reno and Vegas under the condition of congested link capacities for wired network as well as wireless

English

The employment of the existing protocols such as Transmission Control Protocol (TCP) cannot achieve the requirements of high-speed networks such as long term evolution advanced (LTE-A) due to the large-bandwidth and low-latency links used in this network. LTE-A network is the continuation of 3GPP-LTE (3GPP: 3rd Generation Partnership Project) and it is targeted to advanced development of the requirements of LTE in terms of throughput and coverage. Then, LTE-A is not new as a radio access technology, but it is an evolution of LTE to enhance the performance. Therefore, it is necessary to enhance the TCP variants such as improving the congestion control performance over LTE-A to make these variants fulfills the needs of the huge data which transferred over the secured links. This article offered comparative evaluation and estimation of the queue size performed by different TCP source variants over traffic model of LTE-A system using the Network Simulator 2 (NS-2).The queue size measurement proved that TCP Vegas performed better than TCP Tahoe and TCP Reno that are used in the simulation scenario.   Keywords: Long Term Evolution Advanced (LTE-A), queue size, Transmission Control Protocol (TCP), Network Simulator 2 (NS-2).

TCP-CC: cross-layer TCP pacing protocol by contention control on wireless networks

Transmission Control Protocol (TCP) performs poorly over wireless networks. Some research indicates that the TCP congestion control mechanism may cause burstiness in the traffic flow. Numerous TCP segments are delivered simultaneously, while an acknowledgement of a retransmission is successfully received. Burstiness leads to a highly contentious network, which markedly increases the probability of packet loss on wireless networks. TCP pacing is a possible solutions for TCP burstiness on multi-hop networks. In this algorithm, TCP segment transmissions are distributed over the whole Round Trip Time. Most pacing protocols attempt to insert a delay interval into the TCP transmissions. However, there is a similar pacing algorithm in IEEE802.11, known as the contention window mechanism. In this paper, we first measure and analyze the way that the contention window size affects TCP throughput in different scenarios. We propose a cross-layer TCP pacing protocol by contention control in the MAC layer, called TCP Contention Control (TCP-CC). It adjusts the lower bound of the contention window in order to optimize the overall TCP throughput in both one-hop and multi-hop topology. Finally, comparative simulations are conducted in order to verify the improvements of our protocol on both TCP Reno and TCP Vegas.

The Effect of Mobility Models and Traffic Patterns on the Performance of Routing Protocols in MANETs

Mobile ad-hoc networks (MANETs) are self-organizing networks which can form a communication network without any fixed infrastructure. Constant bit rate (CBR) traffic pattern is very well known traffic model for MANETs which generates data packets at a constant rate. Transmission Control Protocol (TCP) provides reliability to data transferring in all end-to-end data stream services on the MANETs. There are several TCP traffic patterns such as TCP Reno, TCP New Reno, TCP Vegas, and TCP Selective Acknowledgment (Sack). The traffic pattern plays an important role in so far as the performance of a routing protocol is concerned. In this paper, we study the effect of impact of mobility models and traffic patterns on the behavior of Reactive (AODV) and Proactive (DSDV, OLSR) routing protocols used in MANETs considering both CBR and TCP traffic patterns with different mobility models namely, Reference Point Group Mobility (RPGM) and Manhattan Grid (MG). The performance metrics used to evaluate the efficiency of the considered protocols are packet delivery ratio, average throughput and End-to-End Delay. The experimental results conducted using NS2 simulator show that the relative ranking of routing protocols may vary depending on both mobility models and traffic patterns.

TCP Performance in Mobile Ad hoc Networks

In this paper, we present a survey of TCP (Transmission Control Protocol) protocol for better performance in the MANET (Mobile Ad Hoc Network). After a short presentation of the main features of TCP, we give the most important problems from which TCP suffer in MANET. We present after that some approaches proposed in the literature in order to improve its performance. Our paper contains also a performance evaluation of TCP NewReno and TCP Vegas transport protocols under AODV and DSR routing protocols. The simulations are conducted under varying conditions of number of TCP connections, number of nodes and mobility.

Performance Comparison between TCP Sack and TCP Vegas using NS-2 Simulator

In this paper, two TCP variants are compared in different scenario. Transmission Control Protocol (TCP) is a reliable, end-to-end transport protocol which is most widely used for data services and is very efficient for wired networks. It also performs well in wireless networks. It is the backbone protocol of most of the internet based applications. Our analysis is on performance of TCP variants. In this paper we carry out performance study of TCP Sack and TCP Vegas to be able to classify which variant of TCP performs better in various possible scenarios. This paper describes an NS-2 based simulation analysis. By varying different parameters and congestion control mechanism we will check its effect on Throughput.

TCP-UB: A New Congestion Aware Transmission Control Protocol Variant

Transmission control protocol (TCP) is a connection oriented protocol for several types of distributed applications. TCP is reliable particularly for traditional fixed networks. With emergence of faster wireless networks, TCP has been performing poorly in its original format. The performance of TCP is affected due to assorted factors including congestion window, maximum packet size, retry limit, recovery mechanism, backup mechanism and mobility. To overcome deficiency of original TCP, Several modifications have been introduced to improve network quality. The mobility is a major hurdle in degrading the performance of mobile wireless networks. In this paper, we introduce and implement new TCP variant University of Bridgeport (UB) that combines the features of TCP Westwood and Vegas. We examine the performance of TCP-UB, Vegas and Westwood using different realistic scenarios. NS2 simulator demonstrates the stability of TCP-UB as compared with TCP Vegas and Westwood in highly congested networks from the mobility point of view.

Comparative Performance Evaluation of TCP Variants in WiMAX (and WLANs) Network Configurations

An important application for the IEEE 802.16 technology (also called WiMAX) is to provide high-speed access to the Internet where the transmission control protocol (TCP) is the core transport protocol. In this paper we study through extensive simulation scenarios the performance characteristics of five representative TCP schemes, namely, TCP New Reno, Vegas, Veno, Westwood, and BIC, in WiMAX (and WLANs) networks, under the conditions of correlated wireless errors, asymmetric end-to-end capabilities, and link congestion. The target is to evaluate how the above conditions would affect the TCP congestion control and suggest the best schemes to be employed in WiMAX networks.

Application of model‐free LQG subspace predictive control to TCP congestion control

AbstractWe investigate the application of a model‐free linear quadratic Gaussian (LQG) subspace‐based predictive controller to Internet congestion control. Specifically, we consider a classically designed LQG linear congestion controller with a non‐standard performance index and determine whether a model‐free controller is a viable alternative in this instance. We employ the model‐free subspace predictive controller methodology which we customize for end‐to‐end transmission control protocol (TCP) congestion control. A series of network simulations support the use of the more easily implementable model‐free controller over its classical analogue. We further demonstrate that the model‐free controller provides increased stability under transient network conditions when compared with the first feedback congestion controller, TCP Vegas. Copyright © 2007 John Wiley & Sons, Ltd.